Glue applicator

ABSTRACT

A glue applicator with a rotating roller having at least one indentation for receiving glue which is to be desposited on a cardboard blank when said blank passes by and contacts the roller. One or more channels in the roller for feeding liquid glue extend to the indentation and are in communication with a source of liquid glue. The roller is intended to be rotated continuously and the glue is fed to each indentation to fill it so that a slight bulb of glue will project beyond the circumferential surface of the roller when the area around the indentation is pressed against the blank.

O United States atelit 1 [111 3,763,823

Nilsson Oct. 9, 1973 GLUE APPLICATOR Primary Examiner-Henry S. Jaudon 75] Inventor .glycldnegneniar Nilsson, Halmstad, Attorney sidney G. Faberet all [73] Assignee: Sprinter Pack AB, Halmstad, [57] ABSTRACT Sweden Aglue applicator with a rotating roller having at least [22] Filed: Jan.3, 1972 one indentation for receiving glue which is to be desposited ona cardboard blank when said blank passes (211 Appl' 2l504l by andcontacts the roller. One or more channels in the roller for feedingliquid glue extend to the indenta- [52} US. Cl. 118/258, 118/261 tionand are in communication with a source of liquid [51] Int. Cl B441111/20 glue. The roller is intended to be rotated continuously [58] Fieldof Search 1 18/258, 259, 261, and the glue is fed to each indentation tofill it so that 1 18/262 a slight bulb of glue will project beyond thecircumferential surface of the roller when the area around the [56]References Cited indentation is pressed against the blank.

UNITED STATES PATENTS 4 Claims, 2 Drawing Figures 2,464,040 3/1949Huebner 118/258 2.597.893 5/1952 Nordquist 118/258 3.066.603

12/1962 Talarico 118/258 PATENTEU DC? 91913 1 GLUE APPLICATOR In theindustrial application of glue on a large scale, the purely manualprocedure using a brush, glue putty knife or the like has been replacedby different mechanical glue spreaders, usually in the form of rollers.As a rule, these devices operate in such a way that a rtating roller ispartly positioned in a glue tray, thus coating its surface with glue.When an article is then pressed against this roller, a portion of theglue is transferred to the article. This transferred glue can becontrolled by the viscosity of the glue, by grooves in the roller, bythe selection of different roller material, etc. Moreover, in order toobtain a more even glue application, several rollers may be used so thatthe glue is transferred to the article by an intermediate roller.

The present invention relates to an improvement of such glue rollers. Inaccordance with the invention the glue is supplied through channels inthe roller to its circumferential surface so as to provide a coatingwith varying glue patterns, coating on uneven cardboard surfaces andjoints between two cardboard layers re spectively, etc.

The invention shall now be described in detail with reference to theaccompanying drawing;

FIG. 1 is a cross section of the glue applicator according to theinvention, and

FIG. 2 is a diagrammatic side viewof the glue applicator with a scraperduring operation.

The glue roller according to the invention comprises an applicatorroller 1 which is rotatably journalled on a cylindrical valve body 3 bymeans of ball bearings 2 and is driven via a sprocket, a pulley or thelike 7 secured to the roller. The applicator roller 1 is formed by aninner spacer sleeve 4, a cylindrical casing and a roller sleeve 6. Thesemembers are sealed against each other with packings 8-11 and secured bynuts and locking screws l2-l4.

The glue applicator herein described is mainly intended for use withthermo-setting glue of the hotmelt type; however, the invention is notrestricted to the use of this type of glue.

When used with thermo-setting glue, the entire glue applicator is keptheated by a centrally positioned heating element 24 so that the glue isprevented from hardening. The temperature is controlled by a thermostatvia impulses sent from a temperature gauge 25.

When the applicator is used, the liquified glue is pumped from a gluesource into the channel in the valve body 3 and is fed via a radial hole16 into an inner slot I7 between the valve body 3 and the inner spacersleeve 4. The glue then passes through a plurality of holes 18 in thesleeve 4 to an outer slot 19 between the spacer sleeve 4 and thecylindrical casing 5. From the slot 19 the glue is fed through aplurality of radial channels 20 in the casing 5 and into a slot 21between the casing 5 and the detachably mounted roller sleeve 6. Grooves23 with the pattern desired on the cardboard blanks to be glued areengraved, milled or the like in the outer surface of the shell 6. InFIG. 1 the groove 23 is shown in cross-section but it is to beunderstood that the longitudinalext'ension of groove 23 on the dream--ferential surface of the roller sleeve may have any desiredconfiguration, length and direction. A number of such grooves may beprovided and separated, and when desired the groove may have such smallextension that it forms a spot. The application of glue often occursonly on some of the flaps on each cardboard blank before they are foldedto form a box or the like. The corlays in production. Furthermore, withthis technique,

the proper amount of glue may be applied in the form of a totallyirregular pattern which may comprise lines of glue in the direction ofmovement of the cardboard and at desired angles relative thereto. Sincethe roller sleeve is easy to replace and because of the relatively lowcost of making the various roller sleeves, the invention provides forthe inexpensive, rapid and effective application of glue in all possiblesituations.

A large number of smaller holes 22 extend radially in the sleeve 6 fromthe slot 21 to the grooves 23 and are spaced apart a distance from 2 to4 mm. The diameter of the holes is somewhat less than the width of thegrooves 23.

The glue is pumped continuously out into the groove 23. via the holes22. Excess glue is scraped away by a scraper 26 and runs down into acollecting vessel from where it returns to the glue container. Byholding the pressure and capacity of the glue pump constant, and bycontrolling the adjustment of the pump by means of a valve, therespective groove 23 will always be filled at the same rate. This rateis so selected that the glue is squeezed out due to its surface tensionsomewhat above the surface of the roller sleeve 6 and will thus lie asan elevation or bulb or ridge over the groove when that portion of theroller comes into contact with the cardboard blank. Should some faultcause an interruption of the supply of cardboard blanks to the glueapplicator, this glue elevation will be scraped away by the scraper,each time the scraper passes by, without the surface of the rollersleeve or other component parts being smeared with glue. The glueapplicator can thus operate regardless of a possible interruption of thecardboard blank supply without any particular measures being necessary,such as shutting off or cleaning the device. I

If the operation continues non stop i.e., without interruptions or othertrouble the scraper has no function to fill. The amount of glue can thenbe regulated so that the quantity pumped out will correspond exactly tothe quantity used during each complete revolution of the roller.

Since the glue in each groove 23 is elevated above the surroundingsurface of the roller sleeve when contact is made with the surface ofthe cardboard blank,

uneven blanks can also be satisfactorily coated with depositing glue ona cardboard blank or the like when the blank passes by and engages theroller surface;

said roller having at least one internal slot for continholes in saidouter sleeve communicating with said recess.

3. The glue applicator of claim 2, further comprising an inner spacersleeve surrounding said shaft and forming a bearing shaft for thecylindrical casing, there being cylindrical glue distributing chamberslocated between said shaft, said spacer sleeve and said cylindricalcasing, which chambers are interconnected via substantially radialchannels in the spacer sleeve for supplying glue to the channels in thecylindrical casing.

4. The glue applicator of claim 3, comprising a scraper bearing againstthe surface of the roller outer sleeve and for scraping off excess gluewhich arises if the supply of cardboard blanks is interruptedmomentarily, or if some other fault occurs.

1. A glue applicator comprising: a shaft; a roller rotatably mounted onsaid shaft; said shaft having a conduit connectable at one end with asource of glue and having a glue feeding opening positioned within theinterior of said roller; said roller having at least one glue receivingrecess along the circumferential surface of the roller for depositingglue on a cardboard blank or the like when the blank passes by andengages the roller surface; said roller having at least one internalslot for continuously coupling the glue feeding opening to said recessto fill only said recess with glue whereby the surface of the glue insaid recess extends beyond the circumferential surface of said roller.2. The glue applicator of claim 1 wherein said roller comprises acylindrical casing surrounding and rotatably journaled on said shaft; adetachably mounted outer cylindrical sleeve containing said recess andbeing mounted for rotation with said casing; a slot being providedbetween said casing and said outer sleeve which slot constitutes adistributing chamber for the glue supplied to the recess through holesin said outer sleeve communicating with said recess.
 3. The glueapplicator of claim 2, further comprising an inner spacer sleevesurrounding said shaft and forming a bearing shaft for the cylindricalcasing, there being cylindrical glue distributing chambers locatedbetween said shaft, said spacer sleeve and said cylindrical casing,which chambers are interconnected via substantially radial channels inthe spacer sleeve for supplying glue to the channels in the cylindricalcasing.
 4. The glue applicator of claim 3, comprising a scraper bearingagainst the surface of the roller outer sleeve and for scraping offexcess glue which arises if the supply of cardboard blanks isinterrupted momentarily, or if some other fault occurs.